Method and apparatus for working elongate components at successive longitudinal locations

ABSTRACT

The invention is concerned with a method of and apparatus for performing a succession of working operations at preselected locations along the length of an elongate workpiece. The leading end of the workpiece is advanced up to a datum position. On the upstream side of the datum position there is located a drive roller, and on the downstream side of the datum position there is located a working station. The work station has at a predetermined distance from the datum position, at least one working tool, for example a saw or a drill. The workpiece is held against the drive roller, and then said drive roller is rotated through a succession of rotary movements, with the drive roller being stationary between movements for predetermined time intervals. During each movement the drive roller is rotated through a predetermined amount. The workpiece is thereby advanced in successive steps through said work station and successive preselected locations longitudinally of the workpiece are brought opposite the working tool, and held stationary for predetermined time intervals between the periods of movement. A second drive roller is located on the downstream side of the work station which is driven in synchronism with the upstream drive roller. Working operations are only performed when the workpiece is stationary.

PATENTEUsEPzs |972 SHEET 1 UF 8 .SGC

mvamorz 'ws Hue# ATTRNEYS United States Patent Hurn [451 Sept. 26, 1972[541 METHOD AND APPARATUS FOR WORKING ELONGATE COMPONENTS AT SUCCESSIVELONGITUDINAL LOCATIONS [72] Inventor: James Hurn, Fre sford,y England[73] Assignee: Hurn Brothers Engineering Limited,

Melksham, Wiltshire, England [22] Filed; April 17,1970 [211vApp1.'N0.;29,ss8

[30] I Foreign Application Priority Data April 17, 1969 Great Britain..'l9,636/69 [52] U.S. Cl ..144/325, l44/24 C, 408/70, 144/3 R [5 l]Int. Cl. .....B27m 3/00 [58] Field of Search ..144/3, 35, 2, l33, 136,325, 144/326, 200, 203, 246, 309; 83/279,'283; 408/70; 143/46 F PrimaryExaminer-Donald R. Schran Attorney-Shoemaker & Mattare [5 7] ABSTRACTThe invention is concerned with a method of and apparatus for performinga succession of working operations at preselected locations along thelength of an elongate workpiece. The leading end of the workpiece isadvanced up to a datum position. On the upstream side of the datumposition there is located a drive roller, and on the downstream side ofthe datum position there is located a working station. The work stationhas at a predetermined distance from the datum position, at least oneworking tool, for example a saw or a drill. IThe workpiece is heldagainst the drive roller, and then said drive roller is rotated througha succession of rotary movements, with the drive roller being stationarybetween movements for predetermined time intervals. During each movementthe drive roller is rotated through a predetennined amount. Theworkpiece is thereby advanced in successive steps through said workstation and successive preselected locations longitudinally of theworkpiece are brought opposite the working tool, and held stationary forpredetermined time intervals between the periods of movement. A seconddrive roller is located on the downstream side of the work station whichis driven in synchronism with the upstream drive roller. Workingoperations are only performed when the workpiece is stationary.

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mvENTOR A/mf )mm ATTORNEYS PATENTEDSEP as |912 SHEET 6 UF 8 mm N BON BONmmfm INVENTOR" SHEET 7 UF 8 INVENTOR ATTORNEYS METHOD AND APPARATUS FORWORKING ELONGATE COMPONENTS AT SUCCESSIVE LONGITUDINAL LOCATIONS Thisinvention relates to methods and apparatus for positioning an elongateworkpiece, such as a length of timber `or of metal in bar, sheet,tubular, or other form, so that it may be cut or worked at anypreselected place along its length.

This invention has for one object to provide a method and apparatuswhereby an elongate workpiece may be brought to positions where it maybe accurately worked, e.g., by sawing, trenching, milling, shearing ordrilling at successive locations along its length with manualintervention during such working operations being minimal.

ln the case of a length of timber for use in a frame for a building, itmay be necessary to perform a large number and variety of operationsover the length of the timber. Thus, it may be required to form with atrenching tool a plurality of recesses of differing depths and widthsand at differing intervals along one side of the length, and along theopposite side of the length a further set of recesses which differ fromthose on the first side both as regards their spacing from one anotherand as regards the dimensions of the individual recesses. Furthermore,the same length may require to have holes of differing sizes formed init at a variety of intervals over its length. All these operations maydiffer from one another and may require as to their location greataccuracy. A timber floor ioist of 12.0 feet length may require as manyas 25 different operations over its length and even though such a job isusually produced in batches, the setting up time for each batchnecessitated for manual production by pattern and jig is verydisadvantageous and costly.

Broadly stated the invention provides a method of performing asuccession of working operations at preselected locations along thelength of an elongate workpiece which includes the steps of advancingthe leading end of the workpiece up to a datum position, on the upstreamside of which datum position there is located a drive roller, and on thedownstream side of which datum position there is located a workingstation with, at a predetermined distance from the datum position, atleast one working tool; holding the workpiece against said drive roller,and then rotating said drive roller through a succession of rotarymovements, with the drive roller being stationary between movements forpredetermined time intervals, and during each movement being rotatedthrough a predetermined amount, all whereby said workpiece is advancedin successive steps through said work station and successive preselectedlocations longitudinally of the workpiece are brought opposite theworking tool, and held stationary for predetermined time intervalsbetween the periods of movement.

During the periods when the workpiece is stationary, a working operationwill be performed upon it. For example, if there is but one tool, theworkpiece will be progressively advanced past the tool and this will beemployed for a working operation each time the workpiece stops. However,and more usually, a variety of operations is required for a singleworkpiece and to this end a number of working tools may be located atthe work station each at a known distance from the datum position.

For example, at 2 feet from the datum position there may be arranged tomake passes into the opposite sides of a timber length, a pair oftrenching tools. At a further interval from the datum position there maybe arranged a first drill and at a still further interval, a seconddrill having a differently sized bit. In such a case the workpiece willbe advanced in such manner as to bring successive locations opposite therequisite tools which are then selectively operated. It will beunderstood that although each tool will be arranged to move or passthrough the workpiece the trench cut, or the drilled hole, so formedwill always be at a predetermined known distance from the datumposition, which controls the starting position for the workpiece.

The successive rotary and part rotary movements of the driven roller mayreadily be controlled by way of a positional gear box and the drive fromthe gear box is conveniently by shaft and worm and pinion gearing toavoid back-lash. Preferably also, one or more of such driven rollers isarranged at each side of the work station so that movement of theworkpiece may be controlled even after it has passed out of engagementwith the roller on the upstream or input side of the work station. It isessential that all driven rollers are driven in synchronism preferablyfrom the same drive shaft.

The datum line is required in order to establish the position of theleading end of the workpiece relative to the drive roller or rollersbefore the workpiece enters the work station. The roller or rollers thenadvance the workpiece over a succession of measured movements past thedatum line. During each successive movement, the roller or rollers arerotated a predetermined amount and hence the leading end of theworkpiece is moved a corresponding distance further away from the datumposition.

The datum position may take mechanical form as an end stop which ismoved initially into the path taken by the workpiece before it reachesthe work station. The leading end of the workpiece is moved intoabutment with the end stop. The workpiece is then urged against thedrive roller or rollers and the instantaneous position of the roller orrollers at this time is established as a start position from which allsubsequent successive rotations or partial rotations can be measured.Accordingly the end stop which has enabled the start position of thedrive roller or rollers to be established, can now be removed and theworking procedure commenced.

In an alternative arrangement, the datum position can be constituted bya switching device, e.g., photo electric switch means, or by an electromechanical trigger switch. Such switch will be actuated by the leadingend of the workpiece as it passes the switch. The start position of thedrive roller or rollers will then be established by operation of theswitch and the successive rotary movements of the drive roller orrollers can be measured from the start position.

Above each driven roller and co-operating therewith is an idler rollerwhich bears on the workpiece to prevent slip between the workpiece andthe driven roller.

The idler roller is arranged for upward and downward movement toaccommodate workpieces of different thickness, and conveniently apneumatic ram and cylinder assembly effects the movement of the idlereither to a position out of engagement with the workpiece or to aposition where it bears on the workpiece and urges it against theco-operating driven roller. v

In certain cases, it is envisaged, for some jobs, that three or moreworkpieces can conveniently. be

processed simultaneously by being laidv together and passed through themachine in this condition. This will notalways be possible with thickerworkpieces or with all possible working operations.

It is considered preferable for the workpiece to rest on thel drivenroller and to have the idler roller located above the workpiece andoperative to press it downwardly on to the driven roller. y

However, if the nature of the workpiece so dictates both the drivenroller and the operating idler roller could rotate about vertical axeswith the workpiece being sandwiched between them.

Advantageously, each working tool, be it a trench saw or drill, willhave associated with it means for clamping the workpiece so that theworkpiece will be steadied at the required location, when thatparticular tool performs its operation on the workpiece.

Pneumatic circuitry with rams and cylinders conveniently control thevarious clamping devices.

As the workpiece passes through the machine it will be urged laterallyagainst a fixed fence and will bear against idler rollers. When theworkpiece is stopped for the performance of a working operation, theclamping devices will operate laterally to hold the workpiece againstthe fixed fence.

Such fence will constitute a datum from which can be measured thedistance across the width of the workpiece of a location at which a toolis to perform its work. v

The tool may be adjusted to this distance again by pneumatic circuitrywhich will then cause the tool to operate the workpiece in a verticalpass either upwardly or downwardly.

After the pass, the clamping means are disengaged and the drive rollersoperated to advance the workpiece to bring a different longitudinallocation opposite the same tool or to bring the same longitudinallocation just worked opposite a different tool.

The various successive operations of the pneumatic circuitry for theclamps and tools, are readily susceptible to control by preprogrammedtape with the aid of a positional sequence and control mechanism ofknown kind. Such a mechanism is also conveniently employed to drive thepositional gearbox for driving in synchronism the advance drive rollers.

It will be appreciated that the accurate functioning of the machine willto a large extent be dependent on the accuracy with which the driverollers effect successive advance movements and stoppages of theworkpiece and that such accuracy will be impaired if the workpiece slipson the drive rollers.

To this end it is preferably to employ a number of drive rollers eachwith its own co-operating idler pressure roller and each driven insynchronism preferably by split worm gear drive from a singletransmission shaft. In one practical embodiment the drive rollers havediameters of 24 inches and the ratio of the worm drive gearing is 24 lso that each rotation of the transmission shaft represents l inch ofadvance movement. Accelerations during advance and braking movements maybe kept low without disadvantage since while the workpiece is beingmoved the opportunity is available to position one or other tool for thenext working operation. Provided that the accelerations are belowin./sec.2 satisfactory operation is reliably obtained.

When programmed tape control is employed, the programming of 25successive operations performed on 12 feet length of floor joist may beobtained on a 3 foot length of tape. This, together with say, a drawingis the only record necessary to keep in anticipation of a repeatoperation. This has to be compared with the present necessity of storinglarge patterns.

Again using this example of a l2 feet length with 25 successiveoperations, 15 of which are trenching and l0 drilling, the setting uptime of a machine according to the invention equipped with trenching anddrilling heads, is only that occasioned by identification and retrievalof the tape followed by feeding of the tape to the control mechanism. Sosoon as the latter is started the first workpiece is fed to the machine.With this must be compared the conventional methods of employingpatterns and jigs; with the identification and retrieval of the largepattern from store and lthe setting up time of the jig.

Actual production of individual workpiece may involve a time saving of 5l, a saving on manpower of 3 1 and a significant increase in accuracy.Perhaps most important of all, the risk of human injury is greatlyreduced.

By way of example, the invention will now be described in greater detailwith reference to the accompanying drawings, in which,

FIGS. 1A, 1B and 1C are views of typical finished wooden buildingcomponents,

FIG. 2 is a side elevational view of an embodiment of the apparatus ofthe present invention,

FIG. 3 is a plan view corresponding to FIG. 2,

FIG. 4 is a view of a driven roller unit along the line IV-IV of FIG. 2,and is to a greater scale than FIG. 2,

FIG. 5 is a side elevational view ofthe driven roller unit of FIG. 4,

FIG. 6 is a view along the line Vl-Vl of FIG. 3,

FIG. 7 is a side view of a second embodiment of apparatus according tothis invention,

FIG. 8 is an end view taken in the direction of the arrow VIII of FIG.7, l

FIGS. 9 and 10 are diagrammatic side views illustrating the mainprinciples of the invention,

FIGS. 9a and 10a are diagrammatic plan views corresponding to the sideviews of FIGS. 9 and l0 respectively.

FIGS. lA, 1B and 1C show typical finished wooden building componentswhich have been trenched and drilled at irregular intervals. Thecomponents of FIGS. 1B and 1C each have been drilled using twodifferently sized bits. It will become apparent from the followingdescription that such components may advantageously be manufacturedusing the apparatus of the present invention. Y

Referring now to FIG. 9, A represents a work station and W is anelongate workpiece over the length of which it is desired to form aseries of working operations by means of tools located in the workstation A. In FIG. 9, C and D represent the working positions of twotools. For example, the tool working at position C may be a trenchingsaw and the tool at position D a drill.

In order to perform a series of working operations accurately on theworkpiece, it is necessary for successive locations of the workpiece tobe brought accurately to positions C or D. To this end the workpiecerequires to be moved in a series of steps along a path indicated byarrow F through the work station A.

According to the invention, such movement is controlled so far as theleading end of the workpiece W is concerned by a drive roller G which isdriven through a succession of rotary movements. The workpiece is heldagainst the drive roller G and is hence advanced in a series of steps.However, the drive roller G being located on the upstream or input sideof the work station will not be able to control advance movement of thetrailing end of the workpiece. Accordingly, there is provided a seconddrive roller H on the output or downstream side of the work station A,which is driven in synchronism with the drive roller G.

In order to obtain accuracy it is necessary to locate the leading end ofthe workpiece W relative to the instantaneous angular position of thedrive rollers G and H and to the working positions C and D at the startof the operation. For this reason it is necessary to have a datumposition which may be constituted or established by a simple mechanicalstop or a photoelectric device. When the leading edge of the workpiece Wis placed at the datum position, the drive rollers can then be startedin rotation to advance the workpiece through a series of measuredmovements from this position. The datum position must be on the upstreamor input side of the first tool of the work station and on the output ordownstream side of a drive rollerfThus in FIG. 9 the datum position mustlie in the region indicated by the arrows J, and for example is at theposition X X.

In FIG. l0 the work station includes an additional tool, for example adrill or a cut off saw operating at position E. Furthermore in this FIG.additional drive rollers G10 and H10 are provided so that the workpieceW may be engaged over an increased area, as compared with thearrangement of FIG. 9, and so reduce the possibility of the workpieceslipping on the drive rollers. All drive rollers are driven insynchronism.

The datum position in the arrangement of FIG. 10 must lie in the regiondesignated by the arrows J 10 and conveniently it is at position X-Xbetween the two input drive rollers G and G10.

Finally, the distance of each working tool from the datum position mustbe known with accuracy.

' In order to maintain the workpiece in engagement with the driverollers and prevent slipping, each drive roller has co-operating with itan idler roller I. Each roller I is movable in the direction of thearrows K, and this accommodates workpieces of different thicknesses.

As will be described with reference to FIGS. 2 to 6 the rollers on theupstream and downstream sides of the work station together with theirrespective cooperating idler rollers I are conveniently constituted assingle drive roller units. l

As will be described with reference to FIGS. 7 and 8 the rollers G andG10 together with their idler rollers I are grouped in a twin rollerdrive unit as are the output rollers H and H10 together with theirrespective idler rollers I.

Reference will now be had to FIGS. 2 to 6 which show in various views anexample of a wood-working machine constructed substantially inaccordance with the general principles described above with reference toFIG. 9.

With reference to FIG. 2, in order to trench, drill or otherwise work ablank baulk or length of timber, the timber length 1 is fed acrossconveyor rollers 2 into the apparatus and its leading end is taken pasta first driven roller unit generally designated 4 which is located onthe upstream side of a datum position constituted by a movable end stop3.

The driven roller unit 4 is arranged to advance the timber length 1eventually to further roller units 4a and 4b. The roller units aresubstantially similar to one another in construction and by way ofexample the unit 4a will now be described in greater detail withreference to FIGS. 4 and 5.

As shown in FIGS. 4 and 5, a drive shaft 5 passes through an oil filledgear box housing 40 mounted on the outside of a driven roller unitcasing 4l. The casing 41 is open ended to permit passage of baulks oftimber. A worm gear 51 is provided on the shaft 5 and engages with agear wheel 42. The gear wheel 42 is mounted on a shaft 43 which extendstransversely of the unit and is carried in bearings 44 on the casing 41.Mounted on the shaft 43 between the bearings 44 is a drive roller 45. Ifthe diameter of the roller 45 is 7.639 inches it will have acircumference of 24 inches. If also there is a reduction of 24 1 betweenthe worm gear 5l and the gear wheel 42, contained within the gear boxcasing 40, for one revolution of the drive shaft 5, and in the absenceof slipping between drive roller 45 and timber length 1, a timber lengthl carried on the drive roller 45 is advanced one inch, and this willclearly facilitate advancement of the baulk by a desired and specifiedamount. Seals 46 may be provided within gear box 40 where the driveshaft 5 enters and leaves the gearbox to prevent leakage of oil from thegear box.

To prevent slipping between each drive roller 45 and a timber length 1,there is provided, above the path which a baulk is intended to take, anidler roller 401. This idler roller is rotatable about a shaft 402carried between levers 403 pivoted about a further shaft 404 carried onthe casing 41 of the roller unit. A transverse strut 405 extends betweenthe levers 403 and is attached to the levers at locations intermediatethe shafts 402 and 404. The strut 405 is pivotally joined at 408 to apiston rod 406 of a pneumatic ram and cylinder unit 407, so that byoperation of the pneumatic ram and cylinder unit 407, the idler roller401 may be raised either to a position indicated at 401a or lowered to aposition indicated at 401b (FIG. 5). The idler roller thus accommodatesand bears down on various sizes of timber length 1 which may be fed intothe apparatus and hence tends to counter any slipping between th baulkand the drive roller 45.

It is envisaged that the stroke of the pneumatic cylinder and ram unit407 may be such as to impart a total upward and downward movement of say2 inches to the idler roller 401, the idler roller being situated atsuch a distance above the drive roller 45 that there may beaccommodated, between the idler roller 401 and the drive roller 45, atimber length of say from 4 to 6 inches in thickness.

It will be appreciated that if it is desired to perform a similaroperation on two or more baulks of lesser thickness, the baulks may befed into the machines one on top of the other, provided only that thetotal thickness of the baulks does not exceed the maximum distancebetween the idler roller 401 and the drive roller 45.

Referring now to FIGS. 2 and 3, the length of timber to be worked isfirst advanced up to the datum position constituted by end stop 3. Abrake 7 prevents rotation of drive shaft until the leading end of thetimber length 1 comes into abutment with the end stop 3. This provides adatum position for the end of the timber length.

End stop 3 is lowered to the position (shown at 3a in FIG. 2) under thecontrol of a pneumatically operated ram and cylinder assembly 8, so thatthe timber length Al is free to advance when driven by the roller unit4.

In the embodiment illustrated, the second drive roller unit 4a issituated on the downstream side of the end stop 3 and its rotation iseffected by the same drive shaft 5 so as to operate in synchronism withthe roller unit 4.

A further drive roller unit 4b is provided on the downstream side of theunit 4a and between these two units is a work station generallydesignated incorporating one or more woodworking tools.

All drive rollers 45 of the units 4, 4a and 4b are driven insynchronism.

In the absence of slipping between the drive rollers 45 and the timberlength l, it is clear that the distance of advancement of the baulk forany given rotation of the drive shaft 5 may easily be ascertained. Thus,if a tool of work station 10, for example, as shown, the blade 100 of asaw or trench is provided at a known distance from the datum positionafforded by the end stop 3, then by rotating drive shaft 5 by apredetermined amount, a point at a desired distance from that end of thetimber length ll which was in abutment with the end stop 3, can bebrought into alignment with the tool, so that an operation, e.g., sawingor trenching, may be performed at any desired point along the baulk.

After a given working operation has been performed the shaft 5 may againbe operated to advance the timber length a predetermined distance andbring it to rest. Slipping may be avoided since accelerations duringadvance and braking movements may be kept low without disadvantage sincewhile the workpiece is being moved the opportunity is available toposition one or other tool for the next working operation. Provided thatthe accelerations are below 165 in./sec.2 satisfactory operation isreliably obtained.

As will be seen in the embodiment illustrated in FIGS. 2, 3, and 6,there are provided two trenching saw blades 100, one on either side ofthe path taken by the timber length, so that trenches may be cut in bothsides of the timber length.

The particular work station 10 comprising two trenching saw, illustratedwill now be described in greater detail with reference to FIGS. 3 and 6.

Motors 101 for the saw or trenching blades 100 are each provided withsets of four rollers 102, each set of four rollers being arranged to runon two substantially vertical tracks 103 carried on posts 107. Each sawblade 100 and motor 101 is adapted to be raised and lowered by apneumatic ram and cylinder assembly 104 which is connected to therespective saw motor 101 by a connecting rod 105. The stroke of eachpneumatic ram and cylinder assembly 104 will be such that the movementafforded thereby to its respective saw is sufficient to move the sawblade from its rest position (as shown in FIGS. 2 and 6) where itscenter is lower in level than the bottom edge of a baulk of timber 1 toa position 100:1 (FIG. 6) where its center would be higher in level thanthe top edge of the thickest baulk the apparatus is arranged to work.

The pneumatic ram and cylinder assemblies 104 are supported by brackets106 carried at the top of the vertical posts 107 which also support thevertical roller tracks 103.

One of these vertical posts 107 is attached at the inner edge of a crossslide 108 carried on rollers 109 which are adapted to traverse ahorizontal track 110 this track being carried on a fixed base membermounted on the base frame of the machine.

Rollers 109a mounted under a second cross slide 108a on the other sideof the work station are arranged to traverse horizontal tracks l10awhich are carried on a third cross-slide 111, the three cross-slides allbeing individually slidable transversely of the path taken by a lengthof timber passing through the machine. This third cross-slide is borneby rollers 112 carried on tracks 113 on a fixed base member 114 mountedon the base frame of the machine.

Guide posts l1 equipped with idler rollers 12 are mounted one at eachinner corner of the third crossslide 111, and further guide posts 11 aremounted one at each inner corner of the fixed base member 115 mounted onthe base frame of the machine. The posts 11 constitute side fences forthe timber lengths, those attached to member 115 being fixed, and thoseattached to cross-slide being movable as described below.

The upper edges of the idler rollers l2 are at the same level as theupper edges of the drive rollers 45 of the units 4, 4a, 4b, and thetimber length is carried on these rollers l2 and 45.

l On the outer edge of the member 114 carrying tracks 113 is mounted avertically extending bracket 116 which is adapted to carry the cylinderof a pneumatic ram and cylinder device 1 17 having a piston rod 118attached to a vertically extending bracket 119a mounted on the outeredge of cross-slide 111. This pneumatic ram and cylinder device 117 andits rod are adapted to move the cross-slide 111, and the secondcross-slide 108a and associated tools and guide posts 11 and guide fencerollers 12 carried thereon, towards or away from the fixed fenceconstituted by the guide post 11 fixed to member l l5, so as toaccommodate different widths of timber between the guide posts 1 l ofthe machine.

At the outer edge of member 115 carrying tracks 1 10 for the firstcross-slide 108 is mounted a vertically extending abutment bracket 119,while to the outer edge of cross-slide 1 1 1 is a similar abutmentbracket l19a.

To the inner surfaces of the brackets 119, 1l9a are attachedsubstantially similar pneumatic ram and cylinder means whichrespectively extend between the inner surfaces 119, 119a and associatedvertical members 107 carried respectively on cross slides 108 and 108aand said ram and cylinder means control the movement of the cross-slides108 and l08a.

The pneumatic ram and cylinder means last above referred to are arrangedthus to move the cross-slides 108 and 108a towards and away from atimber length 1 while the ram and cylinder devices 104 control thevertical movements of the saws relative to the cross-slides. It will beappreciated that similar control means may be associated with othertools mounted on the cross-slides to effect their intended operations onthe timber length.

In the embodiment illustrated, the pneumatic ram and cylinder meanscontrolling horizontal movement of the cross-slides 108 or 108aconsistsv of four cylinders 121, 122, 123, and 124, and associatedpiston rods respectively 131, 132, 133 and 134, the cylinders being yarranged in two pairs, each pair being mounted back to back. Rods 131are attached respectively to brackets 119 or 1l9a and rods 134 to theirrespective vertical member 107.

The cylinders 121, 122, 123, 124 may suitably have respective strokes of1 inch, l inch, $4 inch and 1A; inch to give a total possible movementof the cross-slides 108, 108a of l7/s inches, in 1A; inch steps. Amovement of this amount is found sufficient to accommodate the cuttingof the deepest trenches in baulks of timber which are normally required.

As will be seen from FIG. 3, further pneumatic cylinders 125 aremounted, one on each cross-slide 108, 108a, associated piston rods 135of the pneumatic cylinder means 125 being attached to the respectivevertically extending brackets 119, 119a. These pneumatic ram andcylinder means 125, 135 are arranged to act as checks on the movement ofthe cross-slides 108 and 108a to ensure that the trenches cut byassociated saw means are not deeper than is desired in any particularcase.

Reverting now to FIGS. 2 and 3, a further such driven roller unit 4b isprovided on the downstream side of the work station. The timber length 1is advanced through this further driven roller unit 4b and thence ontooutput conveyor rollers 2a (not shown in FIG. 3) whence the finishedtimber length may be taken to a stockpile or elsewhere.

It will be appreciated that in addition to the saws referred to above,other tool means, for example, drills or routers may be mounted,together with their respective power sources on cross-slides of the workstation 10 such as the cross-slides 108, 108a and it will further beappreciated that saw means may be arranged to traverse a baulkhorizontally rather than vertically as described with reference to flG.6.

It is clear that a further work station and driven roller unit may beincorporated on the downstream side of the driven roller unit 4b betweenthe unit 4b and a further drive roller unit, if the incorporation of allthe desired tool means at one work station 10 would make the distanceacross it, and hence the distance between its two adjacent roller units4a and 4b too great.

The operation of the drive shaft 5 and of the brake 7 as well as of thevarious pneumatic ram and cylinder devices, both those of the rollerdrive units 4, 4a and 4b and those of the, or each, work station aresusceptible of control by commercially available positional and sequencecontrol mechanisms which in turn may be controlled or actuated fromsuitably preprogrammed punched tape.

A typical sequence of operations will be briefly described for theapparatus shown in FIGS. 2 to 6.

Firstly a timber workpiece which has been presawn to length is advancedon the infeed conveyor rollers 2 until it is brought against end stop 3.The upper idler roller 401 of the drive unit 4 engaged with the timberand the end stop 3 is then lowered.

At this stage the work station l0 is in rest condition. In this the ramof cylinder 117 is operated to space the movable fence 1l on slide 111as far as possible from the fixed fence l1 on fixed base member 115; theslides 108 and 108a are held fully withdrawn laterally and the bladesare in a starting position which may be fully up but for the purpose ofthis description will be referred to as fully down with rams fullyextended in cylinders 104.

The shaft 5 is then rotated to advance the workpiece a predetermineddistance and to bring a preselected part of the workpiece opposite theblades 100 which are revolving. The shaft 5 is stopped and the workpiecearrested. The ram 118 is extended to bring the movable fence 11 on slide111 toward the fixed fence so that the workpiece is clampedtherebetween. Ram devices 121, 122, 123, 124 are then operated to moveblade 100 a desired distance into the workpiece and following this orsimultaneously the rams 105 are raised so that the blade 100 performs anupward stroke through the work. The blade is then withdrawn laterallyand lowered to its starting position. lf the operation so requires, theblades 100 on both sides of the work may be in operation simultaneouslywith like or differing cuts or trenches.

After the cutting or trenching has been performed at one locationlongitudinally of the workpiece, the movable fence 11 is disengaged sothat the workpiece may be advanced and stopped by operation of the shaft5 to bring a predetermined new location opposite the tool of the workstation 10. This effected, the workpiece is again clamped between theside fences 11 and operated on by the tool.

It will be appreciated that when the leading end of a workpiece is inthe work station 10, clamping in the vertical sense will be performed bythe roller drive units 4 and 4a and that only after the leading end hasreached unit 4b will this unit assist with vertical clam ping in thearrangement illustrated. It is envisaged, however, that for some jobs avertical clamp may be desirable in the work station itself, Such a clampwould conveniently be mounted on the fixed fence 11.

We refer now to FIGS. 7 and 8, FIG. 8 being an end view taken in thedirection of arrow VIII of FIG. 7. In these Figures is illustrated awood working machine constructed in accordance with the principlespreviously discussed with reference to FIGS. 10 and 10a.

In FIG. 7, A represents a work station incorporating a drill 201operating at a position C, and a trenching saw 202 ldriven by a motor203. The motor 203 is movable vertically on a slide 204 of a post 205under the control of a ram and cylinder device 206. The post 205 ismovable laterally on slides 207 of a machine bed 208, under the controlof a leadscrew 209 driven by a motor (not shown).

On the upstream or input side of the work station A is a twin driveroller unit with drive rollers G and G10 each with a co-operating idlerroller I.

On the downstream or output side of the work station A is a twin rollerdrive unit with drive rollers H and H10 each with a co-operating idlerroller I.

The upstream and downstream twin roller drive units are identical exceptthat the upstream unit has an end stop 4213 movable into or out of thepath of a workpiece W lunder'the control of a ram and cylinder device214. All drive rollers G, G10, H and H are driven in synchronism fromshafts 215 by way of worm and pinion gearing (see FIG. 8). 215a is anintermediate shaft geared to the shafts 215 by-a toothed belt 2l5b (FIG.7).

. As will be seen particularly from FIG. 8 the idler rollers I are eachcarried on a bracket 216 which is equipped with rollers 2.17 engaging invertical tracks of amember 218 fixed in relation to the machine bed 208.The bracket 216 together with idler rollers I are movable verticallyunder the control of ram and cylinder devices 220. This movement is suchas to allow the idler rollers to press timber of predetermined range ofthickness against the drive rollers.

As seen in FIG. 8, a fixed side fence for the workpiece is constitutedby rollers 230 carried in brackets 231 fixed below slide member 218. Amovable side fence is constituted by rollers 232 carried by brackets 233which are slidable laterally on slides 234 fixed in relation to the bed208. Lateral movement of the rollers 232 is effected by ram and cylinderdevices 235. Such lateral movement is required to accommodate workpiecesof different width.

lnoperation the path followed by the workpiece W is indicated by thearrows F. The leading end of the workpiece W is first moved against theend stop 213 which is placed in its path by operation of ram andcylinder device 214. The distance between the end stop 213 and theoperating position C of the drill 201 is known and hence when the endstop 213 has been removed the drive shafts 215 can be rotated to advancethe workpiece along path F to bring a selected location of the workpieceto position C. The tools 201 or 202 or both may then operate on theworkpiece. At all times after stop 213 has been withdrawn and while theworkpiece is engaged with a drive roller, its cooperating idler roller Iwill be urged `downwardly by its ram and cylinder device 220 to pressthe workpiece W against' the drive roller. y

The operation of the various components in correct sequence, includingthe advancing of the workpiece over preselected distances betweensuccessive working operations, is preferably governed by numericalcontrol apparatus of known type.

It will be appreciated that while the embodiments of the inventionillustrated are arranged and intended for operation on timber lengths,the invention is equally applicable to the positioning of otherworkpieces to bring preselected locations opposite working tools.

Iclaim:

l. A method'of performing a succession of working operations atpreselected locations along the length of an elongate workpiece,including advancing said workpiece longitudinally into a machine up to adatum position, sensing the position of said workpiece, engaging theworkpiece with a feed roller positioned before said datum position,pressing on said workpiece from above with at least one idler roller toinsure engagement between said feed roller and said workpiece, causingsaid feed roller to rotate through a predetermined angle of rotation toadvance said workpiece beyond said datum position to a work station at apredetermined distance from said datum position, stopping rotation ofsaid feed roller to stop advancement of said workpiece, performing workon said workpiece at said work station, and automatically causing saidfeed roller to rotate through successive predetermined degrees ofrotation to advance said workpiece successive predetermined distances,with at least some of said predetermined degrees of rotation and thussome of said predetermined distances being different, stoppingadvancement vof said workpiece at the end of each successivepredetermined distance, and performing work on said workpiece atsuccessive predetermined locations longitudinally thereof when saidworkpiece is stopped, so that a variety of successive working operationsmay be performed on said workpiece.

2. A method as defined in claim l including the steps of employingconveying means each comprising at least one drive roller locatedadjacent the path of the workpiece at eachof the upstream and downstreamsides of the work station, and driving said drive roller in synchronismto control advance movement of the workpiece through the work station,and also employing overhead movable idler pressure rollers, oneassociated with each conveying means, to hold the workpiece against theconveying means.

3. A method as defined in claim 2 wherein said working tool is caused tooperate on the workpiece only during time intervals when said driverollers are stationary.

4. A method as defined in claim 2 including providing at least twoworking tools in said work station each at a predetermined distance fromsaid datum position and including the step of causing at least one toolto work the workpiece during each time interval when said drive rollersare stationary.

5. A method as defined in claim l including controlling the accelerationand deceleration of the movements of the workpiece to enhance theaccuracy of movement thereof.

6. A method of performing a succession of working operations atpreselected locations along the length of an elongate workpiece,including advancing Said workpiece longitudinally up to a datumposition, sensing the position of said workpiece, engaging the workpiecewith a feed means in advance of said datum position, pressing on saidworkpiece from above the insure engagement between said feed means andsaid workpiece, advancing said workpiece beyond said datum position to awork station ata predetermined distance from said datum position,stopping advancement of said work-v piece, performing work on saidworkpiece at said work station, and automatically advancing saidworkpiece through successive predetermined distances, with at least someof said successive distancesbeing different, stopping advancement ofsaid workpiece at the end of each successive predetermined distance, andperforming work on said workpiece at successive predetermined locationslongitudinally thereof when said workpiece is stopped, so that a varietyof successive working operations may be performed on said workpiece.

7. A method as defined in claim 6, including controlling theacceleration and deceleration of the movements of the workpiece toenhance the accuracy of movement thereof.

* lll lll

1. A method of performing a succession of working operations atpreselected locations along the length of an elongate workpiece,including advancing said workpiece longitudinally into a machine up to adatum position, sensing the position of said workpiece, engaging theworkpiece with a feed roller positioned before said datum position,pressing on said workpiece from above with at least one idler roller toinsure engagement between said feed roller and said workpiece, causingsaid feed roller to rotate through a predetermined angle of rotation toadvance said workpiece beyond said datum position to a work station at apredetermined distance from said datum position, stopping rotation ofsaid feed roller to stop advancement of said workpiece, performing workon said workpiece at said work station, and automatically causing saidfeed roller to rotate through successive predetermined degrees ofrotation to advance said workpiece successive predetermined distances,with at least some of said predetermined degrees of rotation and thussome of said predetermined distances being different, stoppingadvancement of said workpiece at the end of each successivepredetermined distance, and performing work on said workpiece atsuccessive predetermined locations longitudinally thereof when saidworkpiece is stopped, so that a variety of successive working operationsmay be performed on said workpiece.
 2. A method as defined in claim 1including the steps of employing conveying Means each comprising atleast one drive roller located adjacent the path of the workpiece ateach of the upstream and downstream sides of the work station, anddriving said drive roller in synchronism to control advance movement ofthe workpiece through the work station, and also employing overheadmovable idler pressure rollers, one associated with each conveyingmeans, to hold the workpiece against the conveying means.
 3. A method asdefined in claim 2 wherein said working tool is caused to operate on theworkpiece only during time intervals when said drive rollers arestationary.
 4. A method as defined in claim 2 including providing atleast two working tools in said work station each at a predetermineddistance from said datum position and including the step of causing atleast one tool to work the workpiece during each time interval when saiddrive rollers are stationary.
 5. A method as defined in claim 1including controlling the acceleration and deceleration of the movementsof the workpiece to enhance the accuracy of movement thereof.
 6. Amethod of performing a succession of working operations at preselectedlocations along the length of an elongate workpiece, including advancingsaid workpiece longitudinally up to a datum position, sensing theposition of said workpiece, engaging the workpiece with a feed means inadvance of said datum position, pressing on said workpiece from abovethe insure engagement between said feed means and said workpiece,advancing said workpiece beyond said datum position to a work station ata predetermined distance from said datum position, stopping advancementof said workpiece, performing work on said workpiece at said workstation, and automatically advancing said workpiece through successivepredetermined distances, with at least some of said successive distancesbeing different, stopping advancement of said workpiece at the end ofeach successive predetermined distance, and performing work on saidworkpiece at successive predetermined locations longitudinally thereofwhen said workpiece is stopped, so that a variety of successive workingoperations may be performed on said workpiece.
 7. A method as defined inclaim 6, including controlling the acceleration and deceleration of themovements of the workpiece to enhance the accuracy of movement thereof.